Learning experience re Electric (1 Viewer)

Giddy Lynn

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Hi all

Please excuse the terminology I use as I am not yet up on the technical terms.
Just wanted to pass on this experience I had to all newbies (regulars will know this), regarding plugging in the campsite's electric.

On arrival I plugged in and had TV, battery charger, fridge on, all good, I then went to switch on the hot water heater and electrics switched off! Turned off hot water then reset electric on campsite's EHU box, all good, switched off TV, fridge, turned hot water heater on, electrics shut off again. I went to reception and explained and was told the hot water heater is taking too many (this is where I get mixed up) Amps as they only had 10amps. So we turned everything off and put the hot water heater on again it blew again so we used our gas. To cut a long story short we then turned on what we first had on arrival and it blew again! By the next day we turned everything off except the camping kettle and that blew the electric box. So not having any knowledge of electrics I (wrongly) assumed my MH was at fault and intended to book it in to the garage the next day. As we were packing up the next morning (only booked for 1 night) the warden (who is a member on here) came to me and enlightened me that their electric unit was possibly faulty, and that every time it blew it would take less and less amps until it couldn't take the camping kettle, aargh so it wasn't my MH.

So that weekend I learnt something but I wished I was told sooner. I had a word with the owner so they could put it right even though they already suspected a part needed replacing! Hope that helps any newbies that it may happen to, as had I had the knowledge of this I would have asked to be moved to another unit.
 

Emmit

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So, the campsite knew that they had a fault with their electrics, They knew that in doing what you were doing, you would receive an ever decreasing ampage but they were happy to bu&&er (technical term) you about, take your money and do nothing.
Disgraceful
 
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Feb 24, 2013
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I don't understand the ever decreasing amps bit, 10A should be 10A or nothing, we have an option to set ours to 1, 2 or 3Kw settings which might overcome that issue for us, but most don't have that adjustment

We regularly trip electrics forgetting we have heating on and then using kettle, so much so that we now only boil water on gas (y)
 
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Giddy Lynn

Giddy Lynn

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I don't understand the ever decreasing amps bit, 10A should be 10A or nothing, we have an option to set ours to 1, 2 or 3Kw settings which might overcome that issue for us, but most don't have that adjustment

We regularly trip electrics forgetting we have heating on and then using kettle, so much so that we now only boil water on gas (y)

Like I said I don't understand the terminology but they said it was a part that needed replacing....not sure if it was called a 'reenergiser' or did I just make that up ha ha! It was definitely their unit and not mine.

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Feb 27, 2011
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If I remember my theory correctly, an RCCD operates by having 2 coils wrapped round a single ferite toroidal core. The coils are wrapped in opposite directions so that incoming current is balanced by outgoing current. If there is an inbalance a magnetic field is created proportional to the inbalance. This magnetic field is what causes the trip to trip.
The usual reason for an inbalance is if any current is escaping via earth then it is not returning via the neutral line.

I can kind of imagine a situation where continuous fault situations have caused the toroidal core to become partialy magnetised by a very tiny amount. This may be enough to cause the circuit to trip with a lower current flowing through it than normal. With each trip causing a slight increase in the residual magnetism.

This is just a theory based on my memory from electronics courses from over 25 year ago so may be well clear of the mark. I am happy to be corrected on this one.
 
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Andy in Lossie

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The supply was probably through a standard type B circuit breaker (I don't have my copy of the regs with me so can't remember what the special conditions for camp sites says should be used) as opposed to an RCD (which only isolates a grounding fault rather than an overcurrent fault, unless the site was using RCBOs, which are about 3 times the price of a CB alone) CBs can weaken after being operated several times and unless they are given time to cool down (a minute or so will do) ie. reset straight after tripping, can trip again but at a lower current draw. Which is probably what the warden was aluding to.
 
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Aha @Andy in Lossie another lecky eh? Agree with you, the heating effect would only be temporary and not account for an ever decreasing trip point over an extended period. My guess is they had a hot joint (bad connection which heats up and eventually burns out the connection) in the box which was gradually failing. Hehe just had one of those last night took out one of our main thruster control panels, fortunately when we were tied up safely alongside...

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Giddy Lynn

Giddy Lynn

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I think that the warden is talking nonsense

There was either a fault or not

Can you plug your motorhome in at home and try it there? that way you know what to expect the next time you go to a campsite

We had a few weeks before been on 2 sites which had 18 amps and ran everything on together without a problem. When i plug in at home there is no problem either. It is a learning curve with every outing.
 
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Andy in Lossie

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Hehe just had one of those last night took out one of our main thruster control panels, fortunately when we were tied up safely alongside...
DP thruster? You don't want one of them failing whilst on station!

Yup I was in the airforce for 30 years as a leckie/avionics tech and then offshore pipeline testing and A60 accommodation design and build

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Andy in Lossie

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We had a few weeks before been on 2 sites which had 18 amps and ran everything on together without a problem. When i plug in at home there is no problem either. It is a learning curve with every outing.
Exactly, as Robin said earlier, it was probably the supply post on site. Weak CB or loose connection. A rapid boil kettle plus your hot water boiler will trip some 10 amp supplies mind
 
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just what we needed on the forum..... two more electrical experts..;)

popcorn time :)

The proportion on here does seem a lot higher than the population in general doesn't it?

Even assuming that they aren't all self appointed and do actually know what they're talking about there does seem to be a lot.
 
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scotjimland

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CBs can weaken after being operated several times and unless they are given time to cool down (a minute or so will do) ie. reset straight after tripping, can trip again but at a lower current draw. Which is probably what the warden was aluding to.

may as well get my oar in the water.. :LOL:

This would depend on whether it was a magnetic or thermal/magnet CB

If the former the temperature would affect the time delay, but not affect the trip current

If the later yes, it does need time to cool.. but as you said .. only a minute or so..
 
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Giddy Lynn

Giddy Lynn

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As a matter of interest @Giddy Lynn did you try plugging in to a different elh post?

Also did you check the elh was actually fitted with a 10 amp breaker and not something lower rated?

No didn't try another as it was fairly busy on site and because I had previously gone to reception to tell them I assumed it must be our MH. As far as the 10 amp breaker......what the heck is that (still learning) lol!
 
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Well personally in my many years of experience I think the doubry was not connected to the ubi conuebi 2000 and that the red flashing bit otherwise known as red death should have been connected up his jacksy to synthesise the common sense factor to zero.....:Eeek:


And that my friends is how much I know about lecky, I was lost after the first words...:confused:o_O

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Gorse Hill

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If I remember my theory correctly, an RCCD operates by having 2 coils wrapped round a single ferite toroidal core. The coils are wrapped in opposite directions so that incoming current is balanced by outgoing current. If there is an inbalance a magnetic field is created proportional to the inbalance. This magnetic field is what causes the trip to trip.
The usual reason for an inbalance is if any current is escaping via earth then it is not returning via the neutral line.

I can kind of imagine a situation where continuous fault situations have caused the toroidal core to become partialy magnetised by a very tiny amount. This may be enough to cause the circuit to trip with a lower current flowing through it than normal. With each trip causing a slight increase in the residual magnetism.

This is just a theory based on my memory from electronics courses from over 25 year ago so may be well clear of the mark. I am happy to be corrected on this one.
It's a core balanced transformer used with ELCB, he didn't say it was a RCD trip thou more MCB (overload/current protection) RCD don't provide overload/current protection
Either a contactor faulty or insulation problems, but defo something that needs further investigation
 
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It's a core balanced transformer used with ELCB, he didn't say it was a RCD trip thou more MCB (overload/current protection) RCD don't provide overload/current protection
Either a contactor faulty or insulation problems, but defo something that needs further investigation

Thanks for prompting my memory and pointing out my misunderstanding. I went away and found this video on youtube to show the operation of an MCB to see if I could see how it could fail in this manner.

I have set it to start after his waffle at the beginning.


At about the 7 minute mark he explains the bi-metal breaker operation. You can see a threaded screw at the bottom left which has some white thread lock compound on it.
Perhaps the thread lock has broken down and the screw has worked its way in reducing the the amount of current that is needed to generate the heat required to trip it?
 
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Gorse Hill

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Thanks for prompting my memory and pointing out my misunderstanding. I went away and found this video on youtube to show the operation of an MCB to see if I could see how it could fail in this manner.

I have set it to start after his waffle at the beginning.


At about the 7 minute mark he explains the bi-metal breaker operation. You can see a threaded screw at the bottom left which has some white thread lock compound on it.
Perhaps the thread lock has broken down and the screw has worked its way in reducing the the amount of current that is needed to generate the heat required to trip it?

More likely it's been constantly overloaded and effected the bi-metical

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Emmit

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No didn't try another as it was fairly busy on site and because I had previously gone to reception to tell them I assumed it must be our MH. As far as the 10 amp breaker......what the heck is that (still learning) lol!

Hope I'm not setting myself up for a fall here but Giddy Lynn,

In the UK, usually you get 16amps on the post. The 'stuff' you use in the van is 230volts. If you times the 16amps by the 230volts you get a figure of 3680. These are the watts you have to play with when you use your units.
Your example is easier 10amps x 230volts =2300watts. Your camping kettle is rated at about 1000watts (look on the base). So, when you plugged the kettle in on that site you only had 1300watts left. Your TV could have taken 100wats leaving you with 1200watts. You switched on the water heater @ about 2000watts, and the system said"Too much" and switched itself off at the box.

The lower the rating the EHU from the site, (your site had 10amps) the less 'stuff' you can use. If you should go to France, the norm. is about 6amps with some sites only giving 3-4amps.

Hope the above makes sense. You will soon get used to what individual items in your 'van are rated at what and know which you can use and which you can't.
Regards
 
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Giddy Lynn

Giddy Lynn

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Hope I'm not setting myself up for a fall here but Giddy Lynn,

In the UK, usually you get 16amps on the post. The 'stuff' you use in the van is 230volts. If you times the 16amps by the 230volts you get a figure of 3680. These are the watts you have to play with when you use your units.
Your example is easier 10amps x 230volts =2300watts. Your camping kettle is rated at about 1000watts (look on the base). So, when you plugged the kettle in on that site you only had 1300watts left. Your TV could have taken 100wats leaving you with 1200watts. You switched on the water heater @ about 2000watts, and the system said"Too much" and switched itself off at the box.

The lower the rating the EHU from the site, (your site had 10amps) the less 'stuff' you can use. If you should go to France, the norm. is about 6amps with some sites only giving 3-4amps.

Hope the above makes sense. You will soon get used to what individual items in your 'van are rated at what and know which you can use and which you can't.
Regards

Thanks for that lesson very useful and I am sure I will get the hang of it. I can see how that would cause electric to go off, but obviously showed a fault after switching everything off except the kettle and it still went off. I don't know how people manage on 3-6 amps abroad but with knowledge it will get easier.
 
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